Herbicidal compositions



United States Patent 3 Claims. (Cl. 7194) ABSTRACT OF THE DISCLOSURE Aconcentrated herbicidal salt formulation of a dimethyl long-chain alkylor alkenyl tertiary amine and 4-amino- 3,5,6-trichloropicolinic acidwherein the picolinic acid is present in an amount of at least 17% overthe stoichiometric amount required to form the amine salt.

This application is a division of application Ser. No. 441,881, filedMar. 22, 1965, now US. Patent 3,276,856.

The present invention relates to herbicidal compositions and moreparticularly it relates to an improved composition having a high levelof active herbicidal ingredient and improved emulsification properties.

The use of various plant hormones, particularly hormone acids forcontrolling undesirable vegetation is a well established industrialpractice. Principally used herbicides in the industry are the halo,alkyl, haloalkyl, alkoxy, and amino substituted pyridyl, phenyl andphenoxyalkanoic acids such as, for example,4-chloro-2-rnethylphenoxyacetic acid; 2,4-dichloro and2,4,5-trichlorophenoxyacetic acids; a-(2,4-dichlorophenoxy)- andm-(2,4,5-trichlorophenoXy)-propionic acids; 'y-(2,4,5-trichlorophenoxy)-butyric acid; 2-methoxy-3,6-dichlorobenzoic acid;2-mothoxy-3,5,6-trichlorobenzoic acid; 2,3,6-trichlorophenylacetic acid;2,3,6-trichlor-o-benzoic acid; 2,3,5-triiodobenzoic acid;2,5-dichloro-3-aminobenzoic acid; and 4-amino- 3,5,6-trichloropicolinicacid.

Normally these herbicidal acids, in view of their substantial waterinsolubility and their low level of solubflity in commercialagricultural solvents, are employed in the form of a derivative, suchas, for example, an alkali metal or ammonium salt, an amine salt or asan ester.

Where it is desired to utilize an oil formulation of a herbicide, it hasbeen the practice in the art to employ esters or high molecular weightamine salts in view of the greater ease in dissolving such derivativesin agricultural oils. This procedure, although generally utilized in theherbicide art, is not completely satisfactory for various reasons. Forexample, ester and amine formulations have necessitated the use ofhighly refined and specialized emulsifying agents which are veryexpensive and which add appreciably to the cost of the formulation.Frequently the cost of the emulsifying agent in a given formulationexceeds the cost of the active herbicidal component contained therein,so that the economics of a given herbicidal formulation might bedictated more by the additives employed than the actual active componentutilized there- It is also known in the herbicidal art that these highlyrefined and specialized emulsifying agents are frequently subjected tochemical degradation by acidic components contained in the herbicidalcompositions. This degradation not only results in the destruction ofthe essential emulsifying component, thereby yielding a formulationwhich will not emulsify upon field application, but it also results inreduced storage stability for such compositions thereby greatlyincreasing the problems encountered in attempting to ship and/or storesuch compositions from one season to the next.

So far as the high molecular weight amine salt herbicidal compositionsare concerned these possess a lower amount of active herbicidalcomponent than do ester formulations, so that a greater amount ofherbicidal composition is needed in order to achieve the same totalamount of herbicide application. Moreover, the amine salt formulationshave proven undesirable in view of the toxic nature of some of the aminecomponents employed, and also in view of corrosion problems associatedwith the storage and shipment of amine-type formulations.

It is also well known in the herbicidal art that while conventionaloil-in-water emulsions are relatively easy to form prior to use in fieldapplication, the preferred waterin-oil type emulsions, that is emulsionswherein the oil is a continuous phase, are difficult to prepare andrequire an appreciable amount of work input by way of stirring and/ orshearing in order to form the desired type of emulsions. This, ofcourse, necessitates the employment of specially trained personnel andthe use of specialized equipment which is not always available at thesite of herbicide application.

Beyond the foregoing ditficulties experienced in prior art formulationsof active herbicide acids and derivatives thereof, it is also wellrecognized that many of the derivatives of these herbicide acids possessbiological volatility, whereby vegetation which has not been directlycontacted with the herbicidal component, but which is grmving in fieldsnear the site of application, has been found to be seriously injuredand, in deed, in some cases totally destroyed by the use of suchherbicidal agents.

With the foregoing in mind the principal object of the present inventionis the provision of a novel herbicidal composition which is readilyemulsifiable and which possesses inherent self-emulsification propertiesthereby obviating the need for employment of expensive and highlyrefined emulsifying agents, or specialized equipment and personnel.

A concomitant object of the present invention is the provision of anovel herbicidal composition which contains a high level of activeherbicidal ingredient as compared with prior art formulations.

A further object of the present invention is the provision of aherbicidal composition which possesses no biological volatility andthereby will present no hazard to valuable crops growing in the area ofherbicide applica tion.

Yet another object of this invention is the provision of a stable,concentrated herbicidal formulation which possesses infinite storagelife and which will withstand repeated freeze-thaw cycles.

The present invention is based upon the surprising discovery that a saltformed by the reaction between a tertiary amine of the formula:

wherein R is selected from the group consisting of straight-chain alkyland alkenyl radicals having from 12 to 18 carbon atoms with4-amino-3,5,6-trichloropicolinic acid, is capable of dissolvingappreciable quantities of excess free herbicide acid over and above thatamount which stoichiometrically is required to react with the aminepresent therein to form the amine salt, thereby forming a concentratedherbicidal composition containing high levels of active herbicideingredient and possessing self-emulsifying properties.

The amount of 4-amino-3,5,6-trichloropicolinic acid which is employedwill be that amount which stoichiometrically is required to form theamine salt, plus at least 17% excess acid over and above thisstoichiometric requirement. The exact amount of excess acid will dependupon the solubility characteristics of the particular system employed.For example, more or less of the herbicide acid will be soluble in aparticular amine salt formulation with this acid, and differentsoubility characteristics will generally be encountered in dissolvingthe free herbicide acid into different amine salt formulations fallingwithin the scope of this invention. Accordingly, the upper limit of freeacid is controlled solely by solubility considerations of the particularamine selected and salt thereby produced.

With respect to the tertiary amine, this component must be selected fromthat group of saturated and unsaturated straight-chaindimethylalkylamines having from 12 to 18 total carbon atoms in the alkylchain. Typical amines falling within the scope of this invention includeN,N- dimethyldodecylamine; N,N dimethyltetradecylamine; N,Ndimcthylhexadecylamine; N,N dimethyloctadecylamine; andN,N-dimethyloctadecadienylamine.

The compositions of the present invention are prepared by dissolving thefree 4-amino-3,5,6-trichloropicolinic acid directly into the particulartertiary amine component desired to,-.be used. If the amine is veryviscous at room temperature, and difiicult to flow, it may be warmed tohigher temperatures in order to permit easier handling thereof. Thepreferred practice comprises utilization of a solution of the desiredamine component in an agricultural oil to which the acid is then added.However, utilization of an agricultural oil is not essential for thesuccessful operation of the present invention, and normally is utilizedwhere the viscosity of a particular amine employed, or the amine saltproduced, is such as to render difficult routine handling of thecomposition.

A preferred practice consists in the utilization of mixtures ofcommercially available amines falling within the scope of thisinvention. Such combinations include both saturated and unsaturatedamines having long-chain alkyl groups of from 16 to 18 total carbonsatoms. Amine admixtures of this type have given results which arecompletely acceptable and equivalent to those obtained using a singletertiary amine component. Moreover, the use of commercially availablemixtures of amines from the class described is a more economicalpractice and thus is preferred for this reason.

The agricultural oils which may, if desired, be utilized in preparingthe novel, concentrated, herbicidal compositions of this inventioninclude aromatic oils such as, methylated naphthalenes, and alkylatedbenzenes, such as xylenes and toluenes. The primary function of theseagri-v cultural oils is to lend fluidity to the herbicidal compositionswhich, in certain instances, tend to be very viscous and difficult toflow under normal handling conditions.

Where such oils are utilized it is preferred to incorporate up to about70% by Weight thereof based upon the weight of the formulation. However,as noted hereinabove, formulations falling within the purview of thisinvention can be prepared without the benefit of the agricultural oil orco-solvent.

The discovery of this invention is particularly surprising when it isconsidered that 4-arnino-3,5,o-trichloropicolinic acid is substantiallyinsoluble, or at best, only sparingly soluble, in agricultural oils, sothat the surprising solubility of the amine salt formulations foradditional picolinic acid compound is attributed solely to the aminesalt compositions rather than to any agricultural oils which may beused. Accordingly, the ability of these amine salts to dissolve excessfree 4-amino-3-5,6-trichloropicolinic acid, beyond that amount whichstoicliiometrically is required to form the amine salt, is attributed tothe amine salt compounds per se and is not in any way attributed tosolvency properties of any agricultural oils which may be incorporatedinto the compositions of this invention.

In order to illustrate the surprising properties of the presentinvention there are presented below the results of several formulationswhich have been prepared in accordance with the teachings of thisinvention. It is to be understood, however, that these formulations arepresented herewith solely by way of illustration and are not intended inany way to beconstrued asa limitation of this invention.

4 ExampleI 6.0 grams (0.0203 mol) of N,Ndimethyloctadecenylamine wereadded to grams of mixed Xylene fl'fiCtlOl'lS: To this admixture werethen added 6.0 grams (0.0248

mol) of 4-amino-3,5,6-trichloropicolinic acid with stir ring, at roomtemperature, to yield a clear solution. This formulation contained 22.2%excess free acid over and.

with stirring at room temperature, to yield a complete solution. To thismixture was then added 12.0 grams 0.0497 mol) of4-amino-3,5,6-trichloropicoliuic acid, with stirring, until completesolution was obtained. This particular formulation contained 22.4% ofexcess free 1 acid over and above that amount which stoichiometricallywas required to form the amine salt.

'Simple admixture of the formulation of Example II 1 with water in aratio of 1 part of the formulation to 2 parts of water resulted in arapidly formed water-in-oil emulsion which was stable and suitable forconventional spray applications.

From the formulations presented above it is apparent that it is possiblewithin the purview of this invention to form concentrated herbicidalcompositions possessing unusually high rates of active herbicidecomponent and, moreover, possessing self-emulsification propertiesheretofore unkown in the industry.

I claim:

1. A herbicidal formulation comprising a herbicidally effective amountof an amine salt composition consisting of the reaction product of atertiary amine of the formula:

wherein R is seiected from the group consisting of straight-chain alkyland alkenylradicals having from 12 to 18 carbon atoms with4-amino-3,5,6-trichloropicolinic acid, wherein said picolinic acid ispresent in an amount of at least 17% above that quantity whichstoichiometrically is required to form the amine salt.

2. The amine salt composition of claim 1 whereinthe tertiarystraight-chain alkyl and alkenyl amines having from 16 to 18 carbonatoms in the said alkyl and alkenyl chains.

3. A herbicidal formulation comprising a herbicidally effective amountof an amine salt composition consisting of the reaction product of atertiary amine of the formula:

wherein R is selected from the group consisting of straightchain alkyland alltenyl radicals having from 12 to 18 carbon atoms with aherbicidally effective amount of 4-amino-3,5,6-trichloropicolinic acid,wherein said picolinic acid is present in an amount of at least 17%above that quantity which stoichiometricaly is required to from theamine salt, said formulation also comprising up to 70% by weight of aliquid inert diluent.

References Cited UNITED STATES PATENTS JAMES O. THOMAS, 111., PrimaryExaminer.

amine component comprises admixtures of

